[j-m-o]

The term you're looking for is 'ring-back', and it's original use seems to have gone the way of the do-do in North America.

Most of the PBX/VoIP systems I've worked on (North and South America) provide one arbitrarily to give the caller the warm and fuzzies, regardless of what's actually happening to that call leg.

[kalleboo]

And as a mobile subscriber you can usually pay for a custom "ring-back" tone. So you can bother anyone who calls you with the latest Rihanna hit.